8 NATURE-STUDY LESSONS. 



3. Fasten a silver spoon to the middle of a string. 

 Put an end of the string in each ear. Then slightly 

 swing the spoon until it touches the edge of the table. 

 Note the effect. 



4. Procure two opened cylindrical fruit-cans. Pierce 

 a hole in the bottom of each. Connect the cans with a 

 string or wire by passing it through the holes and fasten- 

 ing it on the inside. Have someone speak into one of the 

 cans; listen with the other at the ear and note the result. 



5. In each of the above cases observe the following: — 

 («) The point at which the sound was produced. 

 (d) The distance at which the sound was heard. 



(c) How the sound reached the ear. 



6. (a) Infer whether sound is conveyed more readily 



through air or through a solid. 

 (i>) Infer the use of wire used in telephoning. 



B. Vibrations of Sound. 



7. (a) Strike a tuning-fork against the table. Observe 



it with the eye and state what you discover. 

 (i>) Strike it again and touch one of the prongs 

 slightly. Note what you observe. (Lacking 

 a tuning-fork, you may use any other kind 

 of steel fork, — a pitch-fork will do.) 



8. (a) Fix a flexible steel needle firmly in a cork which 



will give it sufficient support. Then fasten 

 at the upper extremity a ball of wax, or a 

 piece of paper, or pith, or cork, about the 

 size of a pea. Hold the cork firmly in one 

 hand and strike the needle till you cause it 

 to vibrate. Describe the movements of the 

 wax or paper. 

 (fi) Strike the needle with greater force and state 

 what you observe. 



